LEPRALIA. 



123 



The species given in the plate is Flustra fodacea, 

 a very common zoophyte, and often found on 

 the shore, thrown up by the sea in large masses. 



On many sea-weeds may be found a kind of 

 stony scurf that spreads over their leaves or 

 stems, and often destroys the beauty of the speci- 

 men. It is true that the appearance of the alga 

 may be injured, but the creature that injures it 

 is of so curious and beautiful a form that it ought 

 to be preserved. This stony scurf is called 

 Lepralia, and consists of innumerable cells, not 

 unlike those of the flustra, spread evenly over 

 the surface of the substance to which it adheres, 

 and often so thickly that there is hardly a spot 

 left uncovered. I have now a remarkably fine 

 specimen of Delesseria sanguinea^ measuring eigh- 

 teen inches across, the whole of whose stem, and 

 great part of the leaves, is overrun by several 

 species of Lepralia, which, although they certainly 

 rather disfigure the plant as a dried specimen, 

 look so lovely under the microscope that I would 

 not on any account have them away. 



A common species of Lepralia is depicted on 

 plate E, fig. 6. The upper figure represents the 

 zoophyte as it appears when magnified about 

 thirty diameters, equalling nine hundred times 

 superficially; and the lower figure shows its 



